Waste heat boiler



y April 1o, 1945.y

l.; c." HuFF WASTE HEAT BOILER Filed April 2o FIG.

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INVENTOR LYMAN C. HUFF FIG.

ATTORNEY Patented Apr. 10, 1945 UNITED sTTEs PATENT, OFFICE WASTE HEAT BoILEa Lyman c. Hua, chicago, nl., assignor te Universal Oil Products Company, Chicago, Ill., a. corporation of Delaware Application April 2.0, 1942, Serial No. 439,759

2 Claims. (Cl. 122-34) This invention relates to an improved form of heat exchange apparatus the features of which make it particularly advantageous for use in reclaiming heat from hot combustion gases.

Fig. 4 shows the piping arrangement for a modified form of the invention. I

Fig..5 is an isometric view of a baiiie arrangement which may be. used in applicants invention.

In many exothermic processes quantities vof 5 Referring now to Figs. 1, 2 and 3, the apparaheat are liberated and, unless reclaimed in some tus is made up of an elongated shell II, which'is economical manner, a considerable loss of energy provided at its lower end with the head I2, and is suiered. For example, in the catalytic crack at its upper end with the'ange I3. The ange ing of hydrocarbons a deleterious deposit of car- I3, is adapted to receive the tube sheet I4, to bonaceous or heavy hydrocarbonaceous material l which a plurality of U-shaped tubes I5 are seaccumulates upon the catalyst particles. This cured. Above the, tube sheet is a second elondeposit must be periodically removed to restore gated shell I6, which is provided at its lower end activity to the catalyst and render lt suitable for with the flange I1, and at its upper end with the further use. This is ordinarily accomplished by head lil. The tubesheet is adapted to be secured contacting hot oxygen-containing gases with the l between the two flanges I3 and I'I by means of catalyst to burn the deleterious deposited material bolts not shown. therefrom. This combustion liberates consider- The shell II,l is divided for a substantial porable heat at a relatively high temperature level tion of its length by a baille I9, which is suspended and, for efficient operation, a large portion of this from the tube sheet by means of a plurality of useful heat must be recovered. Various types of hanger rods 20, which engage tapped holes in equipment designed to accomplish the reclamathe tube sheet I4 and drilled holes in brackets 2l, tion of heat from normally waste hot gases have attached to the bale I9, at a point adjacent its been proposed. However, they fail to obviate upper end each drilled hole being large enough certain structural diiii'culties when employed for to permit a rod 20 to freely slide therethrough. heat exchange between fluids of Widely diierent A second baflie 22, is disposed in the lower portemperature and particularly when the temperation of the shell II.. Both the baille I9 and the ture of one or both of the fluids is subject to wide baffle 22- are provided with Slotted holes to oovariations. This is the condition encountered Commodate the tubes |5- A bafe member 23, in generating and/0r Superheating steam, for eX.. provided the Slotted holes 24, iS v attached ample, bv` heat exchange 4with hot combustion 30 t0 the hama I9 by the bolts 25 in Order JO Pre' gases from the regenerating zone of a catalytic Vent the stl'ea'm 0f ht gases from bypassing the cracking system. tubes. This baille arrangement 1s shown more lIn. this invention the incoming hottest gases, cleazjly in F155 of the drawing' instead of rst contacting the tube sheet, as in r Wlth the hama arrangement harem described the usual case, will contact the bent ends of the 3" ubes '5.318 free -to expand downwardly and tubes thereby becoming cooled to a vdegree that itasmgoilrtlfflcdty av' gg; glser'uonger genot-151.5' aiect tm? tube Sheet' are free to expand downwardly because of the onal precaution insulation may be f t th t th 1 tt d h 1 i b m 2 d provided on the tube `sheet to further reduce the ac a e s o e o es r1 e e 2 are ma e h ful ts f th h t y 40 oversized, 1n thevertical direction, to allow for arm e ec o e o gases' thermal expansion of the tubes and baille I 9 -is Ihe yabove mentioned features and advantages free to expand upwardly away from the tubes be as We as addltlonal Ones Wm be made more ap' cause, of the slidable engagement of bracket 2| parent with reference to the accompanying diaandhanger rods 2n. When the appaatus 1s cool grammatic drawing and following description bam@ g Wm be supported by rods 20, but wher; thereof-V the exchanger is hot, baille I9 will be supported by In the dmv/ 111g v the tubes and only maintaining in a vertical posi- Figllis .an elevational view. shown principally tion by brackets 2| s1iaab1y engaging rods 2o.

in Section-ofi@ preferredfform of theinvention- In the sneu n, on opposite sides ofthe bene I Iiga'2s asectional view of the apparatus shown 50 22, and adjacent the head I2, the anged open- 'f -in11'ig.1,`as .taken from the plane indicated.. by ings 26, and 21,'are provided 'as inlet and outlet A fthe-line 2 1.' respectively for the hot gas stream from which y3j isv a sectional view=of` the apparatus y heat is to be reclaimed. Suitable conduits 28 s taken-from the p1ane indiu vand 2l may be secured by bolts, not shown, to

the nausea openings 2s and :1 respectively to direct the hot gas stream into and out of the heat' exchanger.

The upper shell I6, which serves as a water reservoir and steam separating space, is provided with a flanged opening 30 in the head I8 to which may be `secured by bolts, not shown a suitable conduit 3 I, to direct the generated steam to the desired heating or power equipment. A water inlet conduit 32 is provided in the shell I6 for supplying feed water to the boiler. A gage glass 33 or other suitable level indicator may also be provided in the shell I6.

To prevent the agitation of the main body of water in the reservoir from affecting the reading of the gage glass a baffle 34 may be provided disposed longitudinally in the shell I6. Another baille 35 is disposed transverse the shell I6, to facilitate the circulation of water do'wnward through that portion of the tubes I located on the outlet side of baille I9 and upwardly through that portion of the tubes disposed on the inlet side of the baffle I9.

The entire heat exchanger may be supported by the lugs 36, secured to the shell II by welding or other suitable means, and the structural members 31.

The inner wall of the shell II, and that portion of the tube sheet exposed to the hot gases may be covered with a suitable insulating or refractory material 6D to eliminate heat losses through the shell and prevent the tube sheet from attaining excessive temperatures.

In Fig. 4 a modified arrangement of the invention is shown wherein a positive water circulation through the tubes is maintained.

In this arrangement an inlet and outlet header tting 38 is substituted for the upper'shell I6 and attached in its place to the tube sheet I4' and flange I3 by bolts not shown. A reservoir and steam disengaging drum 39 is connected to the outlet side of the tting 38 by means of conduit 40. Water is fed to the reservoir by means of the conduit 4I and is drawn from it by means of conduit 42, which connects to the suction side of pump 43. From the pump 43 water is directed to the inlet side of the tting 38`by means of conduit 44. A suitable expansion joint 45 may be provided in conduit 44 to provide means for dis sipating any thermal expansion in said conduit.

In many regenerating processes the reactivating gases are maintained at relatively high pressures in the neighborhood of about 100 pounds per square inch. When this is the case a portion of these gases may be directed from conduit 29' by means of conduit 46 and valve 41 to a suitable turbine 48 to supply power to drive the water circulating pump 43. A suitable expansion joint '49 may be provided in conduit 46 to allow for the thermal expansion of said conduit.`

In order that suitable pressure will be maintained in the outlet conduit 29 to operate the turbine 48 a back presure regulating valve 50' may be provided in said conduit, the diaphragm 5I of said valve b'eing connected to conduit 29 by means of conduit 52 and .valve 53.

Spent gases from the turbine 48 may be exhausted to atmosphere by means of conduit 64. The drum 39 may be provided with a gage glass 55 or other suitable level indicating device, and steam generatedA in the boiler II and separated from the water in said drum may be directed to suitable heating or power equipment by means of conduit 56.

The above description of the invention in two of its preferred forms is used merely as an illustration to point out some of its many features and advantages and is not intended as a limitation of its scope.

I claim as my invention:

1.1In a heat exchanger of the classvdescribed having U-shaped tubes secured at their open ends to a tube sheet and extending downwardly into an elongated vertical shell, a reservoir positioned above said tube sheet in communication with the open ends of said tubes, a longitudinally disposed baille extending within said shell from a point adjacent its lower end to a point spaced from said tube sheet intersecting said tubes at approximately the mid-points of their bends comprising an upper section, a lower section and a third section secured to said upper section and slidably engaging said lower section, said sections being slotted to receive said tubes and arranged to prevent passage of `said heat convective fluid at the point of contact with said tubes, means for directing a heat convective fluid into said shell at a point adjacent its lower end and on one side of said baille, means for withdrawing said fluid from said shell at a point on the opposite side of said baille, means for introducing a vaporizable fluid into said reservoir and means for withdrawing evolved vapors from said reservoir.

2. In a waste heat boiler having an elongated vertical shell with closure means at its lower end and a tube sheet disposed transversely near its upper end, a plurality of U-shaped boiler tubes secured at their open ends to said tube sheet and extending downwardly into said shell, a water reservoir positioned above said tube sheet in com. municationwith the open ends of said tubes, a vertical baille disposed within said shell extending from adjacent said lower closure means to a point spaced from said tube sheet and perpendicularly intersecting each of said tubes at their lower extremities comprising an upper section, a lower section and a third section secured to said upper section and slidably; engaging said lower section, said sections being slotted to receive said tubes and arranged to prevent passage of said heat convective fluid at the point of contact with said tubes, means for directing a heat convective fluid into said shell 'at a point adjacent its lower end and on one side of said baffle, means for withdrawing said fluid from said shell at a point on the opposite side of said baille and adjacent the end closure means of said shell, a feed water conduit in communication with said reservoir and 4a steam withdrawal conduit in communication with said reservoir.

LYMAN C. HUFF. 

